The present invention relates to computer systems interconnected by a network, suitably configured to transfer data between one another. A computer system connected to the network processes data from a plurality of data sources. A data source can be an input device attached to the computer system, or can be a storage device, memory, database, or other computer system attached either locally or remotely to the computer system via a network. In the network of computers, at any given time, a computer system may assume a specific role, relative to the processing of data. A computer system that sends a request for data from another computer system is said to be a Client system 1. The computer system that processes requests from other computer systems is said to be a Server system 2. When a Client sends a request for data to a Server, the Server may retrieve some of the requested data from its local resources, and some of the data from an External source 3 on the network. The Server 2 in this case acts as a Client to an External source 3, requesting the appropriate data, and the External source 3 acts as a Server. Thus, a computer system on the network may at one time perform the role of a Client, and at another time perform the role of a Server.
Servers on the network are designed to satisfy requests for a particular type of data. For example, a database server may be designed to accept Structured Query Language (SQL) requests from clients. The database server will execute the SQL and return the resulting database data to the requesting client. A Hyper Text Transfer Protocol (HTTP) server (or Web Server) accepts HTTP request from client systems (generally Web Browsers), processes the requests, and returns the resulting Hyper Text Markup Language (HTML) to the client. In an enterprise business environment, such as the Information Processing environment of a large company, a Server system may accept requests for customer account information. A Client may send the request to the Server in an agreed-upon format, and the Server locates the information within its system or a connected system, then returns the customer account information to the Client. Frequently, in the enterprise business environment, the nature of the large systems involved dictates that the data exchange uses a custom data format instead of an industry standard such as SQL or HTML.
Large corporations often house data in a multitude of sources, such as a host, database, server, or other information source. Often, one computer system may need to retrieve data from many other systems in order to perform its function. Systems in this environment contain complex programs that understand the intricacies of interfacing to each system that contains a data item in need. Such programs are complex to write and maintain, require great expense to development and modify, and are large in size due to the amount of code required for the large number of interfaces. In addition, typical systems access data sequentially, thus perform operations slowly more slowly than if data could be retrieved in parallel. More advanced systems perform some data retrievals in parallel, but the complexity of this type of system requires greatly more experienced programmers and testers, thus significantly increasing the cost of system development. Finally, the code developed to interface to each system and each data source is not easily reused in other systems in the enterprise for a variety of reasons. Program A may be a customer service application and may access servers 1, 2, and 3. Program B developed by another group may be a billing system that accesses servers 1, 2, and 4. Some reasons for low success rate of reuse are the fact that programs perform vastly different functions (service vs. billing), so developers often do not recognize the possibilities of reusing code. Tools to assist in reuse are not widely used, developers are generally slow to be convinced that existing components will precisely fit their needs, and current engineering practices that emphasize reuse have not been widely adopted in many corporations. In the cases where code is reused, it often is copied and customized by a programmer, requiring work for the customization and testing for the resulting implementation.
When a Client requires data from many different sources, it must contain a method and apparatus to send a request to each Server providing each type of required data. The Client also must have a method and apparatus to both receive the response data from the Server and to make sensible use of the data. Likewise, a Server needs a method and apparatus to process requests from Clients, and return resulting data to them. In the typical enterprise computer system environment, the methods and apparatuses for both Client and Server must be developed, integrated, tested, and deployed.
The methods and apparatuses necessary for a Client to usefully retrieve and process data from a Server is called an Interface. The code components involved in an Interface are shown in FIG. 3. The Client makes a request from the Request Code 4, which contains the method and apparatus to send the request to the Server and receive the result. The Request Code uses information from the Data Source Description Code 5 component located on the Client, which contains the method and apparatus to identify how to physically connect and maintain a connection to the Server. The Server component contains a Service Processor 6 that contains the method and apparatus to receive the request, cause the Server to process the request, then return the results to the Client. The Request Code for the Client receives the request, then identifies and interprets each element of information in the return using the method and apparatus contained in the Parsing Code 7. In total, 4 components must be developed for each interface.
Many computer systems use standard interface components such as those supporting SQL requests to database management systems (DBMS) to drastically reduce development time. Unfortunately, many computer systems in large enterprise environments require interfaces customized for the particular Client and Server pair. For these systems, a large number of interface components must be developed. As an example, assume two client systems interface with 4 server systems as shown in FIG. 3. Each server requires a Service Processor. Each Client requires Request Code, Server Description Code, and Parsing Code for each interface, therefore Client 1 requires 9 components and Client 2 requires 9 components, for a total of 22 total development components for the depicted interfaces. It is possible for Clients to share interface components, for example, Client 2 can reuse the code developed in Client 1 for its interface to Server 1. However, it is more often the case in large enterprise environments for Client 1 and Client 2 to be developed by separate groups, and the opportunity to reuse the code is not exploited.
There is a need for an interface strategy that organizes the implementation of the interface components, so that interface components are only developed a single time, regardless of the number of Clients implementing similar interfaces to various servers. This would result in fewer development resources being expended, because many of the interface components would be developed a single time, instead of once for each Client system.
Client systems generally request data in a sequence of steps. For example, a customer service application may perform the following sequence of processing steps: 1) obtain a customer phone number from the user, 2) request account information such as name, address, and account number from a Server, 3) send request to another Server to retrieve current order information, 4) send a request to the same server to retrieve order detail information, 5) send request to yet another Server to request service contact history. Each request in the sequence requires a different parameter in order to carry out the request. The original customer account request requires the customer's phone number. The request to retrieve order information requires an account number that is retrieved with the account information. The request to retrieve order detail requires an order number, which is retrieved with the order information. The request to return service contact information requires an account number. The cumulative data comprising customer account, order information and service history can be said to be a single Data File constituting the current status of the customer. The specification of the contents of a Data File is said to be the Document Definition of the Data File. Though a more formal specification is required in practice, in the current example, the Document Definition would state that the Data File contains account, order, and service history information. A Client can thus request a single data file for a particular customer, even though the source information is stored in separate Servers.
Szlam et al. (U.S. Pat. No. 5,675,637) describe a means and apparatus for obtaining and displaying data with sequentially dependent information. However, there is a need to automatically obtain sequences of information from a plurality of data sources where vastly different Clients are supported. There is a need for defining the cumulative data file independent of any display, rendering, or presentation system, so that Clients of vastly differing types can obtain full information without developing interface code. For example, a customer data file as in the above example would be useful for a desktop client, a browser-based client, an Interactive Voice Response (IVR) unit or Voice Response unit (VRU), a hand-held computer, an invoice printing system, and a vast assortment of other uses.
Many servers provide conglomerations of data in a predetermined format. But since different types of clients have different formatting needs, there is a need for the information in the resulting data file to be formatted according to client preference, without having to create a new Document Definition for the data file. If a client has a particular format requirement, there is a need for the data file to be made to conform to this new format for this client, and for said new format to be further available to other clients upon request. The ability to render the same information in different formats is enabled by abstracting the information itself from the format of the information.
Current DBMS Servers satisfy requests for data that is generally row-based. Row-based data is appropriate for clients in many instances, such as requesting data that will populate a visual table on a display screen. Often, a Client desires more complex information, as in the case of the customer Data File in the above example. A DBMS cannot process a request for an arbitrarily complex hierarchy in a single request, because requests to a DBMS are row-based. Instead, multiple requests to the Server are required to obtain data representing an arbitrarily complex set of data. There is a need for data servers to support arbitrarily complex hierarchies of data. International standards such as those defining SGML and XML support data file formats that represent arbitrarily complex hierarchies of data. Hierarchies can, of course, represent rows of data just as a DBMS does, plus other arbitrary sets of data.
Current Servers supporting delivery of Data Files generally retrieve the Data File from a source, or generate the Data File in code, then return it to the Client. The resulting Data File is fixed in size and information content, regardless of whether the client needs the entire set of information. For clients requiring less than the entire set of information, this very inefficient, as unneeded data is generated, formatted, and transmitted to the client. The client must read and parse the entire Data File. There is a need for clients to be able to flexibly select only those portions of the Data File that suits their particular purpose at the time.
Current DBMS's are Servers that act on data requests of clients. One advanced data manipulation feature of these systems (Oracle, Sybase, Informix, Microsoft SQL Server) is to perform a join operation on table data. Oracle is one example DBMS that allows a join across data tables on different Servers, even servers running different vendor's DBMS. But the join is limited to row-based tables, with the result of the join being row data.
There is a need for Clients to be able to request a join of data that has rich, hierarchical information, such as the customer Data File in the above example. The join operation should also not be constrained to operate on a particular source of data, such as a DBMS, but rather should work on data from any source whatsoever.
Current Servers can easily handle Data Files that are completely static. However, if some or all of the data file is dynamic, an intricate program must be developed to produce the dynamic portions and insert them appropriately into the Data File. Microsoft's Active Server Pages and Allaire's Cold Fusion are examples of systems that simplify mixing dynamic with static data for internet-based Data Files. However, these systems do not provide the capability to generate arbitrary levels of hierarchical data, so are limited in the complex data structures they can generate. There is a need to easily define static and dynamic portions of a Data File, while not limiting the complexity of the resulting data.
Such a method is difficult to change when the needs of the client system changes. The present invention provides a single data file generation engine, which can construct an infinite number of different types of data files. To enable the generation of a new type of data file, a user simply creates a new DDF and ensures the DDF is accessible to the Data Server. To make a modification to an existing type of data file, the user simply edits the DDF with the current inventions Authoring System, then the next time that type of data file is requested, the new format is used. All changes are effected with no changes to the software code, therefore no programmer must be hired to make the changes. New data file types and changes to existing data file types are easily made by an administrator.